Introduction:

A lever is useful if you can balance it like a see saw, and then push just a little bit harder. To learn the laws of leverage, we start with the laws of balance. A simple mathematical test make it possible to predict whether a lever will be balanced or not. Once you know that, you can figure out how to lift very heavy things!

Activity:

Use the balance beams and complete the tasks show by the teacher.

• Task 1: Create as many balances as you can with one washer on each side. What's the general rule for balancing these washers?
• Task 2: Create as many balances as you can with one washer on one side and two washers on the other (two washers on the same peg for now). What's the general rule for balancing these washers?
• Task 3: Create as many balances as you can with one washer on one side and three washers on the other (three washers on the same peg for now). What's the general rule for balancing these washers?
• Task 4: Create as many balances as you can with two washers on one side (same peg) and three washers on the other (same peg for now). What's the general rule for balancing these washers?

Conclusion:

What is the general rule for balancing a balance beam? Can you predict whether a beam will balance?

Practice:

• Foundation

• Mastery

If you got those answers right, go back and figure out how you could balance any unbalanced beams! Write out your solutions!

• Expertise

If you could balance the unbalanced beams, makeup four of your own balance beams situations, and give an answer key!

Enrichment:

Balance, an Oscar-winninganimated short film, used the laws of balnace to make a profound statement.